DESCRIPTION: Two specific aims were delineated: First, morphological, immunohistochemical, and molecular genetic evidence suggest that measles virus is present in otosclerotic lesions. Paramyxoviruses have been implicated in other osseous dysplasias (e.g. Paget's disease). The investigators plan to search for measles virus RNA in otosclerotic temporal bones. The applicant wi draw upon the extensive archival collection at the Massachusetts Eye and Ear Infirmary (MEEI) which includes 205 sets of otosclerotic temporal bones. Recently, the osteogenesis imperfecta (OI) associated gene COL 1A1 has been implicated in otosclerosis. The hypothesis is that otosclerosis represents a minor variant of OI and possesses a similar dysfunction in type 1 collagen. They have in hand samples from 220 individuals from 65 families with otosclerosis. The second line of investigation involves mtDNA mutations associated with presbycusis. The MEEI archival temporal bone collection contains 142 sets of temporal bones with various types of presbycusis (28 sensory, 70 neural, 44 strial). Comprehensive audiological profiles are available. Sensorineural hearing loss is present in virtually all known varieties of mitochondrial dysfunction. Mitochondrial mutations appear to accumulate with advancing age. The investigators plan to search for a variety of point mutations as well as sequential deletions in mtDNA obtained from their archival collection. Collection of audiological data from patients with known mitochondrial mutatio will also be undertaken.